/* * From linux/include/uapi/linux/btrfs_tree.h * * SPDX-License-Identifier: GPL-2.0+ */ #ifndef __BTRFS_BTRFS_TREE_H__ #define __BTRFS_BTRFS_TREE_H__ #include #define BTRFS_VOL_NAME_MAX 255 #define BTRFS_NAME_MAX 255 #define BTRFS_LABEL_SIZE 256 #define BTRFS_FSID_SIZE 16 #define BTRFS_UUID_SIZE 16 /* * This header contains the structure definitions and constants used * by file system objects that can be retrieved using * the BTRFS_IOC_SEARCH_TREE ioctl. That means basically anything that * is needed to describe a leaf node's key or item contents. */ /* holds pointers to all of the tree roots */ #define BTRFS_ROOT_TREE_OBJECTID 1ULL /* stores information about which extents are in use, and reference counts */ #define BTRFS_EXTENT_TREE_OBJECTID 2ULL /* * chunk tree stores translations from logical -> physical block numbering * the super block points to the chunk tree */ #define BTRFS_CHUNK_TREE_OBJECTID 3ULL /* * stores information about which areas of a given device are in use. * one per device. The tree of tree roots points to the device tree */ #define BTRFS_DEV_TREE_OBJECTID 4ULL /* one per subvolume, storing files and directories */ #define BTRFS_FS_TREE_OBJECTID 5ULL /* directory objectid inside the root tree */ #define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL /* holds checksums of all the data extents */ #define BTRFS_CSUM_TREE_OBJECTID 7ULL /* holds quota configuration and tracking */ #define BTRFS_QUOTA_TREE_OBJECTID 8ULL /* for storing items that use the BTRFS_UUID_KEY* types */ #define BTRFS_UUID_TREE_OBJECTID 9ULL /* tracks free space in block groups. */ #define BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL /* device stats in the device tree */ #define BTRFS_DEV_STATS_OBJECTID 0ULL /* for storing balance parameters in the root tree */ #define BTRFS_BALANCE_OBJECTID -4ULL /* orhpan objectid for tracking unlinked/truncated files */ #define BTRFS_ORPHAN_OBJECTID -5ULL /* does write ahead logging to speed up fsyncs */ #define BTRFS_TREE_LOG_OBJECTID -6ULL #define BTRFS_TREE_LOG_FIXUP_OBJECTID -7ULL /* for space balancing */ #define BTRFS_TREE_RELOC_OBJECTID -8ULL #define BTRFS_DATA_RELOC_TREE_OBJECTID -9ULL /* * extent checksums all have this objectid * this allows them to share the logging tree * for fsyncs */ #define BTRFS_EXTENT_CSUM_OBJECTID -10ULL /* For storing free space cache */ #define BTRFS_FREE_SPACE_OBJECTID -11ULL /* * The inode number assigned to the special inode for storing * free ino cache */ #define BTRFS_FREE_INO_OBJECTID -12ULL /* dummy objectid represents multiple objectids */ #define BTRFS_MULTIPLE_OBJECTIDS -255ULL /* * All files have objectids in this range. */ #define BTRFS_FIRST_FREE_OBJECTID 256ULL #define BTRFS_LAST_FREE_OBJECTID -256ULL #define BTRFS_FIRST_CHUNK_TREE_OBJECTID 256ULL /* * the device items go into the chunk tree. The key is in the form * [ 1 BTRFS_DEV_ITEM_KEY device_id ] */ #define BTRFS_DEV_ITEMS_OBJECTID 1ULL #define BTRFS_BTREE_INODE_OBJECTID 1 #define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2 #define BTRFS_DEV_REPLACE_DEVID 0ULL /* * inode items have the data typically returned from stat and store other * info about object characteristics. There is one for every file and dir in * the FS */ #define BTRFS_INODE_ITEM_KEY 1 #define BTRFS_INODE_REF_KEY 12 #define BTRFS_INODE_EXTREF_KEY 13 #define BTRFS_XATTR_ITEM_KEY 24 #define BTRFS_ORPHAN_ITEM_KEY 48 /* reserve 2-15 close to the inode for later flexibility */ /* * dir items are the name -> inode pointers in a directory. There is one * for every name in a directory. */ #define BTRFS_DIR_LOG_ITEM_KEY 60 #define BTRFS_DIR_LOG_INDEX_KEY 72 #define BTRFS_DIR_ITEM_KEY 84 #define BTRFS_DIR_INDEX_KEY 96 /* * extent data is for file data */ #define BTRFS_EXTENT_DATA_KEY 108 /* * extent csums are stored in a separate tree and hold csums for * an entire extent on disk. */ #define BTRFS_EXTENT_CSUM_KEY 128 /* * root items point to tree roots. They are typically in the root * tree used by the super block to find all the other trees */ #define BTRFS_ROOT_ITEM_KEY 132 /* * root backrefs tie subvols and snapshots to the directory entries that * reference them */ #define BTRFS_ROOT_BACKREF_KEY 144 /* * root refs make a fast index for listing all of the snapshots and * subvolumes referenced by a given root. They point directly to the * directory item in the root that references the subvol */ #define BTRFS_ROOT_REF_KEY 156 /* * extent items are in the extent map tree. These record which blocks * are used, and how many references there are to each block */ #define BTRFS_EXTENT_ITEM_KEY 168 /* * The same as the BTRFS_EXTENT_ITEM_KEY, except it's metadata we already know * the length, so we save the level in key->offset instead of the length. */ #define BTRFS_METADATA_ITEM_KEY 169 #define BTRFS_TREE_BLOCK_REF_KEY 176 #define BTRFS_EXTENT_DATA_REF_KEY 178 #define BTRFS_EXTENT_REF_V0_KEY 180 #define BTRFS_SHARED_BLOCK_REF_KEY 182 #define BTRFS_SHARED_DATA_REF_KEY 184 /* * block groups give us hints into the extent allocation trees. Which * blocks are free etc etc */ #define BTRFS_BLOCK_GROUP_ITEM_KEY 192 /* * Every block group is represented in the free space tree by a free space info * item, which stores some accounting information. It is keyed on * (block_group_start, FREE_SPACE_INFO, block_group_length). */ #define BTRFS_FREE_SPACE_INFO_KEY 198 /* * A free space extent tracks an extent of space that is free in a block group. * It is keyed on (start, FREE_SPACE_EXTENT, length). */ #define BTRFS_FREE_SPACE_EXTENT_KEY 199 /* * When a block group becomes very fragmented, we convert it to use bitmaps * instead of extents. A free space bitmap is keyed on * (start, FREE_SPACE_BITMAP, length); the corresponding item is a bitmap with * (length / sectorsize) bits. */ #define BTRFS_FREE_SPACE_BITMAP_KEY 200 #define BTRFS_DEV_EXTENT_KEY 204 #define BTRFS_DEV_ITEM_KEY 216 #define BTRFS_CHUNK_ITEM_KEY 228 /* * Records the overall state of the qgroups. * There's only one instance of this key present, * (0, BTRFS_QGROUP_STATUS_KEY, 0) */ #define BTRFS_QGROUP_STATUS_KEY 240 /* * Records the currently used space of the qgroup. * One key per qgroup, (0, BTRFS_QGROUP_INFO_KEY, qgroupid). */ #define BTRFS_QGROUP_INFO_KEY 242 /* * Contains the user configured limits for the qgroup. * One key per qgroup, (0, BTRFS_QGROUP_LIMIT_KEY, qgroupid). */ #define BTRFS_QGROUP_LIMIT_KEY 244 /* * Records the child-parent relationship of qgroups. For * each relation, 2 keys are present: * (childid, BTRFS_QGROUP_RELATION_KEY, parentid) * (parentid, BTRFS_QGROUP_RELATION_KEY, childid) */ #define BTRFS_QGROUP_RELATION_KEY 246 /* * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY. */ #define BTRFS_BALANCE_ITEM_KEY 248 /* * The key type for tree items that are stored persistently, but do not need to * exist for extended period of time. The items can exist in any tree. * * [subtype, BTRFS_TEMPORARY_ITEM_KEY, data] * * Existing items: * * - balance status item * (BTRFS_BALANCE_OBJECTID, BTRFS_TEMPORARY_ITEM_KEY, 0) */ #define BTRFS_TEMPORARY_ITEM_KEY 248 /* * Obsolete name, see BTRFS_PERSISTENT_ITEM_KEY */ #define BTRFS_DEV_STATS_KEY 249 /* * The key type for tree items that are stored persistently and usually exist * for a long period, eg. filesystem lifetime. The item kinds can be status * information, stats or preference values. The item can exist in any tree. * * [subtype, BTRFS_PERSISTENT_ITEM_KEY, data] * * Existing items: * * - device statistics, store IO stats in the device tree, one key for all * stats * (BTRFS_DEV_STATS_OBJECTID, BTRFS_DEV_STATS_KEY, 0) */ #define BTRFS_PERSISTENT_ITEM_KEY 249 /* * Persistantly stores the device replace state in the device tree. * The key is built like this: (0, BTRFS_DEV_REPLACE_KEY, 0). */ #define BTRFS_DEV_REPLACE_KEY 250 /* * Stores items that allow to quickly map UUIDs to something else. * These items are part of the filesystem UUID tree. * The key is built like this: * (UUID_upper_64_bits, BTRFS_UUID_KEY*, UUID_lower_64_bits). */ #if BTRFS_UUID_SIZE != 16 #error "UUID items require BTRFS_UUID_SIZE == 16!" #endif #define BTRFS_UUID_KEY_SUBVOL 251 /* for UUIDs assigned to subvols */ #define BTRFS_UUID_KEY_RECEIVED_SUBVOL 252 /* for UUIDs assigned to * received subvols */ /* * string items are for debugging. They just store a short string of * data in the FS */ #define BTRFS_STRING_ITEM_KEY 253 /* 32 bytes in various csum fields */ #define BTRFS_CSUM_SIZE 32 /* csum types */ #define BTRFS_CSUM_TYPE_CRC32 0 /* * flags definitions for directory entry item type * * Used by: * struct btrfs_dir_item.type */ #define BTRFS_FT_UNKNOWN 0 #define BTRFS_FT_REG_FILE 1 #define BTRFS_FT_DIR 2 #define BTRFS_FT_CHRDEV 3 #define BTRFS_FT_BLKDEV 4 #define BTRFS_FT_FIFO 5 #define BTRFS_FT_SOCK 6 #define BTRFS_FT_SYMLINK 7 #define BTRFS_FT_XATTR 8 #define BTRFS_FT_MAX 9 /* * The key defines the order in the tree, and so it also defines (optimal) * block layout. * * objectid corresponds to the inode number. * * type tells us things about the object, and is a kind of stream selector. * so for a given inode, keys with type of 1 might refer to the inode data, * type of 2 may point to file data in the btree and type == 3 may point to * extents. * * offset is the starting byte offset for this key in the stream. */ struct btrfs_key { __u64 objectid; __u8 type; __u64 offset; } __attribute__ ((__packed__)); struct btrfs_dev_item { /* the internal btrfs device id */ __u64 devid; /* size of the device */ __u64 total_bytes; /* bytes used */ __u64 bytes_used; /* optimal io alignment for this device */ __u32 io_align; /* optimal io width for this device */ __u32 io_width; /* minimal io size for this device */ __u32 sector_size; /* type and info about this device */ __u64 type; /* expected generation for this device */ __u64 generation; /* * starting byte of this partition on the device, * to allow for stripe alignment in the future */ __u64 start_offset; /* grouping information for allocation decisions */ __u32 dev_group; /* seek speed 0-100 where 100 is fastest */ __u8 seek_speed; /* bandwidth 0-100 where 100 is fastest */ __u8 bandwidth; /* btrfs generated uuid for this device */ __u8 uuid[BTRFS_UUID_SIZE]; /* uuid of FS who owns this device */ __u8 fsid[BTRFS_UUID_SIZE]; } __attribute__ ((__packed__)); struct btrfs_stripe { __u64 devid; __u64 offset; __u8 dev_uuid[BTRFS_UUID_SIZE]; } __attribute__ ((__packed__)); struct btrfs_chunk { /* size of this chunk in bytes */ __u64 length; /* objectid of the root referencing this chunk */ __u64 owner; __u64 stripe_len; __u64 type; /* optimal io alignment for this chunk */ __u32 io_align; /* optimal io width for this chunk */ __u32 io_width; /* minimal io size for this chunk */ __u32 sector_size; /* 2^16 stripes is quite a lot, a second limit is the size of a single * item in the btree */ __u16 num_stripes; /* sub stripes only matter for raid10 */ __u16 sub_stripes; struct btrfs_stripe stripe; /* additional stripes go here */ } __attribute__ ((__packed__)); #define BTRFS_FREE_SPACE_EXTENT 1 #define BTRFS_FREE_SPACE_BITMAP 2 struct btrfs_free_space_entry { __u64 offset; __u64 bytes; __u8 type; } __attribute__ ((__packed__)); struct btrfs_free_space_header { struct btrfs_key location; __u64 generation; __u64 num_entries; __u64 num_bitmaps; } __attribute__ ((__packed__)); #define BTRFS_HEADER_FLAG_WRITTEN (1ULL << 0) #define BTRFS_HEADER_FLAG_RELOC (1ULL << 1) /* Super block flags */ /* Errors detected */ #define BTRFS_SUPER_FLAG_ERROR (1ULL << 2) #define BTRFS_SUPER_FLAG_SEEDING (1ULL << 32) #define BTRFS_SUPER_FLAG_METADUMP (1ULL << 33) /* * items in the extent btree are used to record the objectid of the * owner of the block and the number of references */ struct btrfs_extent_item { __u64 refs; __u64 generation; __u64 flags; } __attribute__ ((__packed__)); #define BTRFS_EXTENT_FLAG_DATA (1ULL << 0) #define BTRFS_EXTENT_FLAG_TREE_BLOCK (1ULL << 1) /* following flags only apply to tree blocks */ /* use full backrefs for extent pointers in the block */ #define BTRFS_BLOCK_FLAG_FULL_BACKREF (1ULL << 8) /* * this flag is only used internally by scrub and may be changed at any time * it is only declared here to avoid collisions */ #define BTRFS_EXTENT_FLAG_SUPER (1ULL << 48) struct btrfs_tree_block_info { struct btrfs_key key; __u8 level; } __attribute__ ((__packed__)); struct btrfs_extent_data_ref { __u64 root; __u64 objectid; __u64 offset; __u32 count; } __attribute__ ((__packed__)); struct btrfs_shared_data_ref { __u32 count; } __attribute__ ((__packed__)); struct btrfs_extent_inline_ref { __u8 type; __u64 offset; } __attribute__ ((__packed__)); /* dev extents record free space on individual devices. The owner * field points back to the chunk allocation mapping tree that allocated * the extent. The chunk tree uuid field is a way to double check the owner */ struct btrfs_dev_extent { __u64 chunk_tree; __u64 chunk_objectid; __u64 chunk_offset; __u64 length; __u8 chunk_tree_uuid[BTRFS_UUID_SIZE]; } __attribute__ ((__packed__)); struct btrfs_inode_ref { __u64 index; __u16 name_len; /* name goes here */ } __attribute__ ((__packed__)); struct btrfs_inode_extref { __u64 parent_objectid; __u64 index; __u16 name_len; __u8 name[0]; /* name goes here */ } __attribute__ ((__packed__)); struct btrfs_timespec { __u64 sec; __u32 nsec; } __attribute__ ((__packed__)); struct btrfs_inode_item { /* nfs style generation number */ __u64 generation; /* transid that last touched this inode */ __u64 transid; __u64 size; __u64 nbytes; __u64 block_group; __u32 nlink; __u32 uid; __u32 gid; __u32 mode; __u64 rdev; __u64 flags; /* modification sequence number for NFS */ __u64 sequence; /* * a little future expansion, for more than this we can * just grow the inode item and version it */ __u64 reserved[4]; struct btrfs_timespec atime; struct btrfs_timespec ctime; struct btrfs_timespec mtime; struct btrfs_timespec otime; } __attribute__ ((__packed__)); struct btrfs_dir_log_item { __u64 end; } __attribute__ ((__packed__)); struct btrfs_dir_item { struct btrfs_key location; __u64 transid; __u16 data_len; __u16 name_len; __u8 type; } __attribute__ ((__packed__)); #define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0) /* * Internal in-memory flag that a subvolume has been marked for deletion but * still visible as a directory */ #define BTRFS_ROOT_SUBVOL_DEAD (1ULL << 48) struct btrfs_root_item { struct btrfs_inode_item inode; __u64 generation; __u64 root_dirid; __u64 bytenr; __u64 byte_limit; __u64 bytes_used; __u64 last_snapshot; __u64 flags; __u32 refs; struct btrfs_key drop_progress; __u8 drop_level; __u8 level; /* * The following fields appear after subvol_uuids+subvol_times * were introduced. */ /* * This generation number is used to test if the new fields are valid * and up to date while reading the root item. Every time the root item * is written out, the "generation" field is copied into this field. If * anyone ever mounted the fs with an older kernel, we will have * mismatching generation values here and thus must invalidate the * new fields. See btrfs_update_root and btrfs_find_last_root for * details. * the offset of generation_v2 is also used as the start for the memset * when invalidating the fields. */ __u64 generation_v2; __u8 uuid[BTRFS_UUID_SIZE]; __u8 parent_uuid[BTRFS_UUID_SIZE]; __u8 received_uuid[BTRFS_UUID_SIZE]; __u64 ctransid; /* updated when an inode changes */ __u64 otransid; /* trans when created */ __u64 stransid; /* trans when sent. non-zero for received subvol */ __u64 rtransid; /* trans when received. non-zero for received subvol */ struct btrfs_timespec ctime; struct btrfs_timespec otime; struct btrfs_timespec stime; struct btrfs_timespec rtime; __u64 reserved[8]; /* for future */ } __attribute__ ((__packed__)); /* * this is used for both forward and backward root refs */ struct btrfs_root_ref { __u64 dirid; __u64 sequence; __u16 name_len; } __attribute__ ((__packed__)); #define BTRFS_FILE_EXTENT_INLINE 0 #define BTRFS_FILE_EXTENT_REG 1 #define BTRFS_FILE_EXTENT_PREALLOC 2 enum btrfs_compression_type { BTRFS_COMPRESS_NONE = 0, BTRFS_COMPRESS_ZLIB = 1, BTRFS_COMPRESS_LZO = 2, BTRFS_COMPRESS_TYPES = 2, BTRFS_COMPRESS_LAST = 3, }; struct btrfs_file_extent_item { /* * transaction id that created this extent */ __u64 generation; /* * max number of bytes to hold this extent in ram * when we split a compressed extent we can't know how big * each of the resulting pieces will be. So, this is * an upper limit on the size of the extent in ram instead of * an exact limit. */ __u64 ram_bytes; /* * 32 bits for the various ways we might encode the data, * including compression and encryption. If any of these * are set to something a given disk format doesn't understand * it is treated like an incompat flag for reading and writing, * but not for stat. */ __u8 compression; __u8 encryption; __u16 other_encoding; /* spare for later use */ /* are we inline data or a real extent? */ __u8 type; /* * disk space consumed by the extent, checksum blocks are included * in these numbers * * At this offset in the structure, the inline extent data start. */ __u64 disk_bytenr; __u64 disk_num_bytes; /* * the logical offset in file blocks (no csums) * this extent record is for. This allows a file extent to point * into the middle of an existing extent on disk, sharing it * between two snapshots (useful if some bytes in the middle of the * extent have changed */ __u64 offset; /* * the logical number of file blocks (no csums included). This * always reflects the size uncompressed and without encoding. */ __u64 num_bytes; } __attribute__ ((__packed__)); struct btrfs_csum_item { __u8 csum; } __attribute__ ((__packed__)); /* different types of block groups (and chunks) */ #define BTRFS_BLOCK_GROUP_DATA (1ULL << 0) #define BTRFS_BLOCK_GROUP_SYSTEM (1ULL << 1) #define BTRFS_BLOCK_GROUP_METADATA (1ULL << 2) #define BTRFS_BLOCK_GROUP_RAID0 (1ULL << 3) #define BTRFS_BLOCK_GROUP_RAID1 (1ULL << 4) #define BTRFS_BLOCK_GROUP_DUP (1ULL << 5) #define BTRFS_BLOCK_GROUP_RAID10 (1ULL << 6) #define BTRFS_BLOCK_GROUP_RAID5 (1ULL << 7) #define BTRFS_BLOCK_GROUP_RAID6 (1ULL << 8) #define BTRFS_BLOCK_GROUP_RESERVED (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \ BTRFS_SPACE_INFO_GLOBAL_RSV) enum btrfs_raid_types { BTRFS_RAID_RAID10, BTRFS_RAID_RAID1, BTRFS_RAID_DUP, BTRFS_RAID_RAID0, BTRFS_RAID_SINGLE, BTRFS_RAID_RAID5, BTRFS_RAID_RAID6, BTRFS_NR_RAID_TYPES }; #define BTRFS_BLOCK_GROUP_TYPE_MASK (BTRFS_BLOCK_GROUP_DATA | \ BTRFS_BLOCK_GROUP_SYSTEM | \ BTRFS_BLOCK_GROUP_METADATA) #define BTRFS_BLOCK_GROUP_PROFILE_MASK (BTRFS_BLOCK_GROUP_RAID0 | \ BTRFS_BLOCK_GROUP_RAID1 | \ BTRFS_BLOCK_GROUP_RAID5 | \ BTRFS_BLOCK_GROUP_RAID6 | \ BTRFS_BLOCK_GROUP_DUP | \ BTRFS_BLOCK_GROUP_RAID10) #define BTRFS_BLOCK_GROUP_RAID56_MASK (BTRFS_BLOCK_GROUP_RAID5 | \ BTRFS_BLOCK_GROUP_RAID6) /* * We need a bit for restriper to be able to tell when chunks of type * SINGLE are available. This "extended" profile format is used in * fs_info->avail_*_alloc_bits (in-memory) and balance item fields * (on-disk). The corresponding on-disk bit in chunk.type is reserved * to avoid remappings between two formats in future. */ #define BTRFS_AVAIL_ALLOC_BIT_SINGLE (1ULL << 48) /* * A fake block group type that is used to communicate global block reserve * size to userspace via the SPACE_INFO ioctl. */ #define BTRFS_SPACE_INFO_GLOBAL_RSV (1ULL << 49) #define BTRFS_EXTENDED_PROFILE_MASK (BTRFS_BLOCK_GROUP_PROFILE_MASK | \ BTRFS_AVAIL_ALLOC_BIT_SINGLE) #endif /* __BTRFS_BTRFS_TREE_H__ */